反硝化细菌、硝酸钙和锆改性沸石联用对底泥中氮磷迁移转化的影响及硝态氮释放风险评估

本文考察了基于反硝化细菌、硝酸钙和锆改性沸石的组合技术（CN+DB+ZZ）对底泥中氮磷迁移转化的影响,并探讨了该技术的硝态氮释放风险.结果发现,单一的硝酸钙处理（CN）虽然可以有效地抑制底泥中磷的释放,但是会造成上覆水体的氨氮和硝态氮污染.硝酸钙和反硝化细菌联合处理（CN+DB）尽管可以有效地抑制底泥中磷的释放,并降低上覆水体的硝态氮二次污染风险,可是却无法有效地控制底泥中氨氮的释放.硝酸钙和锆改性沸石联合处理（CN+ZZ）虽然可以有效地抑制底泥中磷和氨氮向上覆水体的释放,但却会造成上覆水体硝态氮的二次污染.CN+DB+ZZ组合处理技术不仅可以有效地控制底泥中磷的释放,而且可有效降低底泥中氨氮的释放速率,并且与CN和CN+ZZ技术相比还可降低上覆水的硝态氮二次污染风险.CN+DB+ZZ组合技术对底泥中磷与铁同步释放的抑制、对底泥中氧化还原敏感态磷的削减、以及对底泥吸附磷酸盐和氨氮能力的增强,对于其控制底泥中磷和氨氮的释放是至关重要的.以上结果说明,CN+DB+ZZ组合技术是一种非常有希望的用于控制水体底泥中磷和氨氮释放的方法.     

铁碳微电解及沸石组合人工湿地的废水处理效果

铁碳微电解填料和沸石由于对废水中污染物具有良好的处理效果,因而被作为基质逐渐运用于人工湿地中.本研究构建了铁碳微电解填料+砾石（湿地A）、铁碳微电解填料+沸石（湿地B）、沸石（湿地C）以及砾石（湿地D）为基质的4组人工湿地,并利用间歇曝气对湿地系统进行增氧,探究不同填料对人工湿地废水处理效果的影响.结果表明,与湿地D相比,铁碳微电解填料显著提高了湿地出水的溶解氧含量（DO）（P<0.05）和pH（P<0.05）;4组人工湿地对有机物的去除率均达到95%以上,且各组间不存在显著性差异（P>0.05）;对TN而言,湿地A、B和C的平均去除率分别比湿地D提高了7.94%（P<0.05）、9.29%（P<0.05）和3.63%（P<0.05）,铁碳微电解填料和沸石对提升人工湿地TN去除效果的贡献率分别为73.55%和26.45%;各组湿地对NH₄⁺的平均去除率为67.93%~76.90%,与湿地D相比,其它3组湿地均明显改善了NH₄⁺的去除效果（P<0.05）;铁碳微电解填料对湿地NO₃^-的去除效果极佳,去除率高达99%以上,显著高于不添加铁碳微电解的人工湿地系统（P<0.05）.综合对碳氮污染物的处理效果来看,湿地B在间歇曝气的条件下对人工湿地中污染物去除效率最高.     

Improved blending strategy for membrane modification by virtue of surface segregation using surface-tailored amphiphilic nanoparticles

Membrane modification is one of the most feasible and effective solutions to membrane fouling problem which tenaciously hampers the further augmentation of membrane separation technology. Blending modification with nanoparticles (NPs), owing to the convenience of being incorporated in established membrane production lines, possesses an advantageous viability in practical applications. However, the existing blending strategy suffers from a low utilization efficiency due to NP encasement by membrane matrix. The current study proposed an improved blending modification approach with amphiphilic NPs (aNPs), which were prepared through silanization using 3-(Trimethoxysilyl)propyl methacrylate (TMSPMA) as coupling agents and ZnO or SiO₂ as pristine NPs (pNPs), respectively. The Fourier transform infrared and X-ray photoelectron spectroscopy analyses revealed the presence of appropriate organic components in both the ZnO and SiO₂ aNPs, which verified the success of the silanization process. As compared with the pristine and conventional pNP-blended membranes, both the ZnO aNP-blended and SiO₂ aNP-blended membranes with proper silanization (100% and 200%w/w) achieved a significantly increased blending efficiency with more NPs scattering on the internal and external membrane surfaces under scanning electron microscope observation. This improvement contributed to the increase of membrane hydrophilicity. Nevertheless, an extra dosage of the TMSPMA led to an encasement of NPs, thereby adversely affecting the properties of the resultant membranes. On the basis of all the tests, 100% (w/w) was selected as the optimum TMSPMA dosage for blending modification for both the ZnO and SiO₂ types.

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沸石覆盖原位控制湖泊内源中等活性有机磷迁移转化

为揭示湖泊内源中等活性有机磷(MLOP)控制与释放发生机制,采用室内模拟试验,研究沸石覆盖原位控制湖泊内源MLOP迁移转化影响因子.结果表明:酸性水体促进内源MLOP迁移,碱性条件下抑制其转化,不同pH值试验水体沉积物中内源MLOP相对浓度为:[MLOP/TP]pH8>[MLOP/TP]pH7>[MLOP/TP]pH6;温度明显提高内源MLOP迁移水平,低温水体相对高温水体沉积物中内源MLOP含量较低,5℃条件下内源MLOP迁移表观量最大,其随时间迁移量呈幂函数关系,可表示为[MLOP/TP]=0.2823T0.657(R2为0.9709);好氧或厌氧条件下,内源MLOP均发生迁移,且迁移特征和影响效能高度一致,迁移平衡后好氧环境内源MLOP和厌氧内源MLOP相对浓度呈线性相关,可表示为[MLOP/TP]好氧环境=1.0884[MLOP/TP]厌氧环境 -0.0271(R2为99895);光照因子促使内源MLOP迁移,而避光和沸石粒径因素对内源MLOP迁移影响较小;底栖生物颤蚓通过爬行、摄食、掘穴、栖所建造及分泌排泄等一系列活动影响内源MLOP迁移.沸石原位控制湖泊内源MLOP迁移转化效能较弱.     

亲水荷电超滤膜的制备及对腐殖酸的分离性能

为改善聚醚砜(PES)超滤膜的抗污染性能和提高对腐殖酸(HA)的截留率,以介孔二氧化硅(MS)为添加剂,采用相转化法制备了亲水性PES/MS复合超滤膜,并对膜表面进行荷电改性.研究了MS对膜的断面结构、表面化学性质和过滤性能的影响,考察了荷电改性PES/MS超滤膜对水中HA的分离性能以及溶液pH值、离子强度和钙离子浓度等因素对荷电膜超滤过程的影响.SEM表征结果显示,MS颗粒在PES/MS复合膜的表面分散均匀,膜孔的连通性改善.亲水荷电改性后,膜表面接触角由68°降至57°,zeta电位由-6.31mV降至-11.45mV,膜对HA的去除率由72%提高到95%,通量衰减率由29.8%减小到4.9%.结果表明,对PES超滤膜进行亲水荷电改性可有效提高对HA的截留率,同时减轻膜污染;另外,溶液的pH值、离子强度和钙离子浓度对荷电超滤膜的过滤性能有较大影响,调节合适的溶液环境可在提高截留率的同时,减轻膜污染.     

沸石滤池深度处理石化废水二级出水研究

采用小试规模沸石滤池,深度处理石化废水二级出水,通过考察滤池对CODCrNH4^-N和挥发酚的去除情况,分析了沸石去除污染物的规律和机理。结果表明：沸石滤池对CODCr,NH4^＋-N和挥发酚的平均去除率分别达到27．32％、94．67％和34．47％。在滤池运行初期,离子交换起主要作用。随着反应器的运行,离子交换因沸石饱和而减弱,而生物氧化逐渐起作用。由于沸石资源丰富、价格低廉和性能优越,所以沸石滤池作为三级深度处理技术具有广阔应用前景。     

Low-temperature CO oxidation over Au-doped 13X-type zeolite catalysts: preparation and catalytic activity

Au-supported 13X-type zeolite (Au/13X) was synthesized using a common deposition–precipitation (DP) method with a solution of sodium carbonate as a precipitate agent. Further testing was conducted to test for catalytic oxidation of CO. A study was conducted on the effects of different preparation conditions (i.e., chloroauric acid concentration, solution temperature, pH of solution, and calcinations temperature) on Au/13X for CO oxidation. In respect to the catalytic activity, the relationship between different the preparation conditions and gold particles in 13X zeolite was analyzed using X-ray diffraction, TEM and XPS. The activity of Au/13X catalysts in CO oxidation was dependent on the chloroauric acid concentration. From XRD results, a higher chloroauric acid concentration induced larger gold nanoparticles, which resulted in lower catalytic activity. Results revealed that higher temperatures induced higher Au loading, homogeneous deposit, and smaller gold clusters on the support of 13X, resulting in higher CO activity. Furthermore, a pH of 5 or 6 generated greater amounts of Au loading and smaller Au particles on 13X than at a pH of 8 or 9. This may be a result of an effective exchange between Au(OH)2Cl2- and Au(OH)₃Cl^- on specific surface sites of zeolite under the pH’s 5 and 6. The sample calcined at 300°C showed the highest activity, which may be due to the sample’s calcined at 200°C inability to decompose completely to metallic gold while the sample calcined at 400°C had larger particles of gold deposited on the support. It can be concluded from this study that Au/13X prepared from a gold solution with an initial chloroauric acid solution concentration of 1.5 × 10^-3 mol·L^-1 gold solution pH of 6, solution temperature of around 90°C, and a calcination temperature of 300°C provides optimum catalytic activity for CO oxidation.     

钛改性锰矿的除砷效果及机理研究

天然锰矿是一种廉价、易得的除砷矿物材料,为了进一步提高天然锰矿的除砷效果和吸附容量,采用TiCl4对广西桂林天然锰矿进行改性,并对其改性的条件进行优化。实验结果表明最佳的改性条件为:TiCl4浓度为10 mg/L,浸泡时间为18 h,pH=3.05,振荡吸附时间为1 h。与天然锰矿的去除效率(82.95%和77.93%)相比,改性锰矿对As(Ⅲ)和As(Ⅴ)去除率分别可达94.87%和99.31%,相应的饱和吸附量分别为3.48 mg/g和3.27 mg/g,较天然锰矿各自提高了1.25 mg/g和1.21 mg/g。改性锰矿对As(Ⅲ)的吸附符合Freundlich等温吸附模型,对As(Ⅴ)的吸附更符合Langmuir等温吸附模型。     

改性柚子皮吸附剂对模拟废水中Pb^2＋的吸附性能

以废柚子皮为原料,经ZnCl2浸泡一加热的化学改性手段制备改性柚子皮生物吸附剂,并通过模拟试验研究该吸附剂对废水中Pb^2＋的去除。考察了模拟废水的pH、吸附时间、吸附剂用量和Pb^2＋初始浓度、温度等因素对柚子皮吸附剂去除Pb^2＋的影响,并研究柚子皮吸附剂对Pb^2＋的吸附动力学及吸附特征。结果表明,模拟废水的pH、吸附时间、吸附剂用量和Pb^2＋初始浓度、温度等因素对柚子皮吸附剂吸附废水中Pb^2＋均有显著影响。适宜的吸附条件为pH5．3-6．5,吸附时间1．5h,吸附剂用量10g·L^-1,Pb^2＋初始质量浓度100mg·L^-1,温度30℃。在该条件下,废水中Pb^2＋去除率在90％以上。柚子皮吸附剂对废水中Pb^2＋的吸附符合动力学二级反应方程,等温吸附规律可用Langmuir、Freundlich和Temkin模型进行较好的描述。     

天然沸石对农田退水中氨氮的去除

利用静态吸附实验研究了沸石颗粒大小、氨氮初始浓度、接触时间及Na+离子浓度等因素对天然白银沸石去除模拟黄灌区农田退水中氨氮(NH4+-N)效果的影响,同时研究了吸附等温线特征,并考察了其吸附机理.研究结果表明,沸石颗粒大小、接触时间及NH4+和Na+初始浓度对NH4+-N交换容量都会产生一定影响;根据复相关系数(R2),NH4+-N的吸附等温线更符合三参数等温线模型;而对于两参数等温线模型,Langmuir模型比Freundlich模型能更好地描述NH4+-N在天然沸石上的离子交换过程;NH4+-N吸附实验数据与Elovich模型拟合最好(R2≥0.9766).研究结果表明了天然白银沸石是一种适合NH4+-N去除的离子交换剂,可用于黄灌区农田退水中NH4+-N的去除.